It is necessary for an automobile producer to estimate the number of miles per gallon (mpg) achieved by its cars. suppose that the sample mean for a random sample of 60 cars is 29.4 mpg and assume the standard deviation is 2.2 mpg. now suppose the car producer wants to test the hypothesis that μ, the mean number of miles per gallon, is not 28.9. conduct a test using a significance level of α=.05 by giving the following: (a) the test statistic(b) the p -value (c)the final conclusion is a. there is not enough evidence to support the claim. b. there is enough evidence to support the claim. the time needed for college students to complete a certain paper-and-pencil maze follows a normal distribution with a mean of 30 seconds and a standard deviation of 4 seconds. you wish to see if the mean time μ is changed by vigorous exercise, so you have a group of 15 college students exercise vigorously for 30 minutes and then complete the maze. it takes them an average of x¯=27.1 seconds to complete the maze. use this information to test the hypothesesh0: μ=30ha: μ≠30conduct a test using a significance level of α=0.01.(a) the test statistic(b) the positive critical value, z0 =(c) the final conclusion is